Control of a transporter based on attitude

Abstract

A transporter for transporting a load over a surface. The transporter includes a support platform for supporting the load. The support platform is characterized by a fore-aft axis, a lateral axis, and an orientation with respect to the surface, the orientation referred to as an attitude. At least one ground-contacting element is flexibly coupled to the support platform in such a manner that the attitude of the support platform is capable of variation. One or more ground-contacting elements are driven by a motorized drive arrangement. A sensor module generates a signal characterizing the attitude of the support platform. Based on the attitude, a controller commands the motorized drive arrangement.

What is claimed is: 
     
       1. A method for steering a transporter, the transporter having a support platform flexibly coupled to at least two laterally-disposed wheels, each of the at least two laterally-disposed wheels being associated with a separate motor, a controller calculating torque for each of the separate motors individually, the controller commanding a motorized drive arrangement, the method comprising:
 calculating, by the controller, a first torque for one of the separate motors and a second torque for another of the separate motors, the first torque and the second torque based at least on a signal characterizing an attitude of the support platform; 
 commanding, by the controller, the motorized drive arrangement to apply the first torque to one of the at least two laterally-disposed wheels through the one of the associated separate motors and the second torque to another of the at least two laterally-disposed wheels through the other of the associated separate motors; and 
 tracking a first wheel motion of one of the at least two laterally-disposed wheels and a second wheel motion of another of the at least two laterally-disposed wheels to adjust the first torque and the second torque to adjust turning of the transporter. 
 
     
     
       2. The method as in  claim 1  further comprising:
 sensing the attitude based on a distance sensor electronically coupled with the controller. 
 
     
     
       3. The method as in  claim 2  further comprising:
 sensing, by the distance sensor, at least two distances; and 
 adjusting the first torque and the second torque based on a comparison between the at least two distances. 
 
     
     
       4. The method as in  claim 1  further comprising:
 determining the attitude based on user input; and 
 adjusting the first torque and the second torque based on the determined attitude. 
 
     
     
       5. The method as in  claim 4  wherein the user input comprises a position of a center of mass of a load on the support platform. 
     
     
       6. The method as in  claim 4  further comprising:
 determining the attitude based on a power strut controlled by the user input. 
 
     
     
       7. The method as in  claim 1  further comprising:
 determining the attitude based on a power strut controlled remotely. 
 
     
     
       8. A transporter comprising:
 at least two laterally-disposed wheels, each of the at least two laterally-disposed wheels being associated with a separate motor; 
 a support platform flexibly coupled to the at least two laterally-disposed wheels; 
 a motorized drive arrangement driving each of the at least two laterally-disposed wheels associated with the separate motors individually; and 
 a controller commanding the motorized drive arrangement, the controller calculating a first torque for one of the separate motors and a second torque for another of the separate motors, the first torque and the second torque based at least on a signal characterizing an attitude of the support platform, the controller commanding the motorized drive arrangement to apply the first torque and the second torque to the at least two laterally-disposed wheels, the controller tracking a first wheel motion of one of the at least two laterally-disposed wheels and a second wheel motion of another of the at least two laterally-disposed wheels to adjust turning of the transporter, 
 wherein the motorized drive arrangement provides the first torque to one of the at least two laterally-disposed wheels through the one of the associated separate motors and the second torque to another of the at least two laterally-disposed wheels through the other of the associated separate motors. 
 
     
     
       9. The transporter as in  claim 8  further comprising:
 a pivot mechanism flexibly coupling the at least two laterally-disposed wheels to the support platform. 
 
     
     
       10. The transporter as in  claim 8  further comprising:
 a compliant member flexibly coupling the at least two laterally-disposed wheels to the support platform. 
 
     
     
       11. The transporter as in  claim 8  wherein the support platform comprises a fore-aft axis and a lateral axis. 
     
     
       12. The transporter as in  claim 8  wherein the attitude comprises an orientation with respect to the ground. 
     
     
       13. The transporter as in  claim 8  further comprising:
 a sensor module determining the attitude, the sensor module being coupled to the controller. 
 
     
     
       14. The transporter as in  claim 13  wherein the sensor module comprises at least one distance sensor, the at least one distance sensor measuring a measured distance characteristic of the attitude of the support platform. 
     
     
       15. The transporter as in  claim 14  wherein the measured distance characteristic comprises a distance between a fiducial point on the support platform and the ground. 
     
     
       16. The transporter as in  claim 14  further comprising:
 a reflector reflecting a distance signal generated by the at least one distance sensor. 
 
     
     
       17. The transporter as in  claim 16  wherein a distance from the at least one distance sensor to the ground is calculated based on a time or phase difference between when the distance signal was generated by the at least one distance sensor and when the reflected distance signal is received by a sensor receiver. 
     
     
       18. The transporter as in  claim 14  wherein the at least one distance sensor comprises at least one contact sensor.